What Are Prenatal Vitamin Supplements and What Do They Do?
Key takeaways:
Prenatal vitamins are important for both pregnant people and developing fetuses.
People who are pregnant have some specific nutritional needs. And a prenatal vitamin, along with a healthy diet, can help fill those needs.
Talk with a healthcare professional about what ingredients you need in your prenatal vitamin. Common ones include folic acid, iron, and omega-3 fatty acids.
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Table of contents
Because of the nausea, fatigue, and constipation that often accompany pregnancy, many people find it difficult to consistently eat a balanced diet while pregnant. Prenatal vitamins are important for a healthy pregnancy, because they provide additional nutrients that you may not be getting from your diet.
But there are specific ingredients to look out for when choosing a prenatal vitamin. This is because being pregnant means having some unique nutritional needs.
What are prenatal vitamins?
Prenatal supplements contain specific vitamins and nutrients important for a healthy pregnancy, some of which may be difficult to get enough of through diet alone. There are a variety of brands and types of prenatal vitamins available, including those designed to target some more specific nutritional needs.
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In general, prenatal vitamins contain the vitamins and minerals needed to help you and your growing fetus maintain healthy levels of important nutrients. Studies suggest that prenatal vitamins improve outcomes in the growth and development of the fetus, especially during the first trimester of pregnancy.
Benefits of prenatal vitamins
There are many benefits to prenatal vitamins, for both yourself and your growing fetus. These include:
Providing higher amounts of essential nutrients for your fetus’ development, such as folic acid and iron
Supplying important nutrients you may not get through diet alone, such as omega-3 fatty acids
Replacing nutrients you may be losing due to vomiting from morning sickness
Providing you with nutrients that may be depleted during pregnancy or breastfeeding, such as calcium and vitamin D
Keep in mind that you should only take one serving of your prenatal vitamin each day unless instructed otherwise. (Read the label to find out how many pills are in one serving of your prenatal vitamin.) Some multivitamin ingredients can be harmful when taken in large amounts. Too much vitamin A, for example, may harm your fetus.
When should you start taking prenatal vitamins?
It’s best to start taking a prenatal vitamin before you conceive. This is because there are certain vitamins that are crucial for a fetus’ growth.
For example, folic acid is especially important for the development of the fetus’ spinal cord and brain. These tissues can develop very early on, before you even know you are pregnant.
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So, it’s recommended to start taking folic acid at least a month before trying to become pregnant. Since pregnancy sometimes happens unexpectedly, some people of reproductive age take a prenatal vitamin on the chance they do become pregnant.
If you are of childbearing age and there’s a chance you might get pregnant in the next few months, it’s a good idea to start taking a prenatal vitamin now, instead of waiting until you know you’re pregnant. If you find out you are pregnant and haven’t been taking a prenatal vitamin, don’t worry. Just start taking one as soon as you can.
Are there benefits to taking prenatal vitamins if you’re not pregnant?
If you aren’t pregnant or trying to get pregnant, you don’t need to take prenatal vitamins. A balanced diet should provide the nutrients you need. And prenatal vitamins may contain certain ingredients that cause side effects in healthy adults who don’t need the additional nutrients.
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But if you’re trying to become pregnant or think it’s possible you will get pregnant, it’s a good idea to start taking prenatal vitamins.
What is in prenatal vitamins?
As mentioned above, the most important ingredient in your prenatal vitamin is folic acid, which you need for the fetus’ brain and spinal cord development. This need is crucial before and during pregnancy, especially in the first trimester. Prenatal vitamins contain at least 400 mcg of folic acid.
Folic acid, a form of vitamin B9, is naturally present in some foods, such as:
Beans
Oranges
Nuts and seeds, like walnuts and chia seeds
Leafy greens, such as spinach, broccoli, and mustard greens
Eggs
Avocados
Apart from these foods, you can also consider whole grains or other products that may be fortified with folic acid. But even if you have a varied diet, it can be very difficult to get enough folic acid from food to support a growing fetus.
Additional prenatal vitamin ingredients
In addition to folic acid, there are other important nutrients needed to support a healthy pregnancy. You can get many of them through a balanced and nutritious diet. But you can also get them through a prenatal vitamin. Below, we discuss four of these nutrients.
1. Calcium
Most pregnant people need at least 1,000 mg of calcium daily to support their fetus’ bone and tooth development — and protect their own bones. For some, it may be hard to get enough calcium through foods like dairy and leafy green vegetables and fortified foods. Prenatal vitamins are a way to supplement this.
Prenatal vitamins vary on how much calcium they contain. So it’s a good idea to check labels and review your calcium intake with your obstetrician before picking one.
2. Iron
Iron helps with red blood cells and oxygen delivery to the fetus. And low iron levels can lead to anemia. So pregnant people need at least 27 mg of iron daily. But not all prenatal vitamins contain iron, so check your prenatal vitamin’s label carefully to make sure it does.
Also, since anemia is common during pregnancy, some people need iron supplements in addition to their prenatal vitamin. So it’s a good idea to review your iron needs with your healthcare professional in case you need additional supplementation.
3. Omega-3 fatty acids
Omega-3 fatty acids are important for a fetus’ brain and eye development. So pregnant people need at least 1.4 g of these fatty acids daily. This is most important in the third trimester, when the fetus’ brain is rapidly developing.
Omega-3 fatty acids are naturally found in:
Cold-water fatty fish, such as salmon
Nuts
Flaxseed (ground or as oil)
Chia seeds
Avocados
While eating fish has many health benefits, it’s important to be aware of the mercury content of certain fish. Fish with high mercury levels should be avoided during pregnancy.
4. Vitamin D
Like calcium, vitamin D is important for a fetus’ bone and tooth development. So pregnant people should get at least 600 IU daily. Some people may need more.
You can get vitamin D naturally from sun exposure and by eating certain foods, like milk and salmon. But many people need additional supplementation.
Important nutrients you can get through food
There are many other nutrients that are important during pregnancy, but most people get enough of them through a healthy, balanced diet alone. These include:
Talk to your healthcare professional if you’re worried you may not be getting enough of these nutrients.
Are there any side effects of prenatal vitamins?
Prenatal vitamins, especially if they contain iron, can cause gastrointestinal side effects, such as:
Nausea
Constipation
Bloating
Gas
Many people already experience these symptoms during pregnancy, so it may be hard to tell if your prenatal vitamin is to blame. Talk with your healthcare professional if you notice any unusual symptoms and you think your supplement could be the source.
What is the best prenatal vitamin?
The best prenatal vitamin for you is the one that you will take regularly. You need one that provides the nutrients you need at a cost you can feel good about. And there are many options that will fit that criteria.
Talk with your healthcare professional about your nutritional needs and other factors to consider when choosing a prenatal vitamin.
Does the FDA regulate prenatal vitamins?
Keep in mind: The FDA doesn’t review over-the-counter (OTC) prenatal vitamins before they enter the market. This means that these vitamins may not contain what they say on the label. They could even contain potentially dangerous contaminants, such as heavy metals.
That’s why it’s best to choose a supplement that has been audited by independent third-party testing companies, such as:
Having one of the above certification seals means that the prenatal vitamin is likely to contain the ingredients stated on its label. Your healthcare professional might also be able to recommend a reliable supplement.
Frequently asked questions
It’s important to take a prenatal vitamin throughout your entire pregnancy, both for you and the developing fetus. Key fetal development takes place from the earliest parts of the first trimester through the very end of pregnancy. Many healthcare professionals recommend that people continue taking prenatal vitamins for several weeks postpartum. This is especially important for people who are breastfeeding, chestfeeding, or bodyfeeding.
Prenatal vitamins provide important nutrients that support pregnant people and developing fetuses. If you are pregnant or think you may get pregnant, you should take a prenatal vitamin.
If you don’t fall into these categories, a prenatal vitamin is likely not necessary. If you aren’t sure whether you need a prenatal vitamin, talk to your healthcare professional.
The bottom line
Getting enough of certain nutrients during pregnancy is essential. And while it’s possible to get most of these nutrients from a balanced and nutritious diet when you are pregnant, some of them — like folic acid — are harder to get from food alone. That’s where prenatal vitamins come in. There are many options when it comes to prenatal vitamins. So work with your healthcare professional to find out what ingredients you need in your vitamin to support you and your growing fetus.
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References
Adams, J. B., et al. (2022). Evidence based recommendations for an optimal prenatal supplement for women in the US: Vitamins and related nutrients. Maternal Health, Neonatology and Perinatology.
American College of Obstetricians and Gynecologists. (2023). Nutrition during pregnancy.
Centers for Disease Control and Prevention. (2024). Folic acid: Facts for clinicians.
Greenberg, J. A., et al. (2008). Omega-3 fatty acid supplementation during pregnancy. Reviews in Obstetrics & Gynecology.
Office of Dietary Supplements. (2022). Folate. National Institutes of Health.
Office of Dietary Supplements. (2023). Calcium. National Institutes of Health.
Office of Disease Prevention and Health Promotion. (2023). Eat healthy during pregnancy: Quick tips.
Oh, C., et al. (2020). Vitamin and mineral supplementation during pregnancy on maternal, birth, child health and development outcomes in low- and middle-income countries: A systematic review and meta-analysis. Nutrients.
Schwalfenberg, G., et al. (2018). Heavy metal contamination of prenatal vitamins. Toxicology Reports.
